DOHA - Saudi Arabia's King Salman arrived in Qatar on Monday as part of a rare regional tour ahead of the annual summit of Arab leaders of the oil-rich Gulf states.

The trip comes at the time of a political transition in the United States and as deadly conflicts rage in Syria, Iraq and Yemen.

Salman began his tour in the United Arab Emirates, a key pillar of a Saudi-led Arab coalition that has been battling Iran-backed Shiite Huthi rebels in Yemen since March 2015.

After Qatar, he will travel on to Kuwait and Bahrain, which is to host this year's Gulf Cooperation Council (GCC) summit .

His trip excludes Oman, known for its warm ties with the kingdom's regional arch-foe Iran and the only GCC member which is not taking part in the Saudi-led coalition. British Prime Minister Theresa May, visiting the Gulf for the first time since she came to office in July, will attend the two-day GCC summit which begins December 6.